Sensing device with whisker elements

A sensing device includes an elongated whisker element having a flexible cantilever region and a base region where a change in moment or curvature is generated by bending of the cantilever region when it contacts an object. One or more sensor elements cooperatively associated with the whisker element provide one or more output signals that is/are representative of two orthogonal components of change in moment or curvature at the whisker base region to permit determination of object distance, fluid velocity profile, or object contour (shape) with accounting for lateral slip of the whisker element and frictional characteristics of the object. Multiple sensing devices can be arranged in arrays in a manner to sense object contour without or with adjustment for lateral slip

Object contour sensing using artificial rotatable vibrissae

Recent research topics in bionics focus on the analysis and synthesis of mammal’s perception of their environment by means of their vibrissae. Using these complex tactile sense organs, rats and mice, for example, are capable of detecting the distance to an object, its contour and its surface texture. In this paper, we focus on developing and investigating a biologically inspired mechanical model for object scanning and contour reconstruction. A vibrissa – used for the transmission of a stimulus – is frequently modeled as a cylindrically shaped Euler-Bernoulli-bending rod, which is one-sided clamped and swept along an object translationally. Due to the biological paradigm, the scanning process within the present paper is adapted for a rotational movement of the vibrissa. Firstly, we consider a single quasi-static sweep of the vibrissa along a strictly convex profile using nonlinear Euler-Bernoulli theory. The investigation leads to a general boundary-value problem with some unknown parameters, which have to be determined in using shooting methods. Then, it is possible to calculate the support reactions of the system. These support reactions together with the boundary conditions to the support, which all form quantities an animal solely relies on in nature, are used for the reconstruction of the object contour. Afterwards, the scanning process is extended by rotating the vibrissa in opposite direction in order to enlarge the reconstructable area of the profile

Haptic robot-environment interaction for self-supervised learning in ground mobility

Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de ComputadoresThis dissertation presents a system for haptic interaction and self-supervised learning mechanisms to ascertain navigation affordances from depth cues. A simple pan-tilt telescopic arm and a structured light sensor, both fitted to the robot’s body frame, provide the required haptic and depth sensory feedback. The system aims at incrementally develop the ability to assess the cost of navigating in natural environments. For this purpose the robot learns a mapping between the appearance of objects, given sensory data provided by the sensor, and their bendability, perceived by the pan-tilt telescopic arm. The object descriptor, representing the object in memory and used for comparisons with other objects, is rich for a robust comparison and simple enough to allow for fast computations. The output of the memory learning mechanism allied with the haptic interaction point evaluation prioritize interaction points to increase the confidence on the interaction and correctly identifying obstacles, reducing the risk of the robot getting stuck or damaged. If the system concludes that the object is traversable, the environment change detection system allows the robot to overcome it. A set of field trials show the ability of the robot to progressively learn which elements of environment are traversable

Engineering and Clinical Evaluation of the VA-PAMAID Robotic Walker

The Veterans Affairs Personal Adaptive Mobility Aid (VA-PAMAID) is a robotic walker that is designed to provide physical support and obstacle avoidance and navigational assistance to frail visually impaired individuals. The goal of this study was to develop and implement testing protocols to determine the performance and safety capabilities of the device and use the results to redesign the walker to make it more reliable and effective.Engineering tests were performed to determine factors such as stability, range, speed, and fatigue strength. Additional tests to characterize the reliability and accuracy of the sensors and avoidance/navigation algorithms were also conducted. The walker traveled 10.9 kilometers on a full charge, and was able to avoid obstacles while traveling at a speed of up to 1.2 m/s. There were no failures during static stability, climatic, or static, impact, and fatigue testing. Some problems were encountered during obstacle climbing and sensor and control testing. Several significant differences were found with respect to the detection distance of the device when varying the obstacle height, material, approach angle, and lighting source. The walker also failed to detect 40-50% of the doorways during the hallway test.Clinical trials were conducted to compare the VA-PAMAID to a low-tech mobility aid (AMD). Subjects were recruited and trained to use both devices efficiently. Each participant was then asked to traverse an obstacle course several times. The time to complete the course, number of wall and obstacle collisions, and number of reorientations were all recorded and averaged. There were no significant differences between the VA-PAMAID and the AMD with respect to collisions or reorientations. The AMD had a significantly lower completion time (p=0.017) than the VA-PAMAID on the obstacle course. The results of the engineering and clinical tests were then used in a house of quality model to determine what factors of the walker needed to be revised. Specific modifications were recommended that would make the device safer, more reliable, and more marketable. Changing the wheel size, mass, component positions, detection algorithm, and other variables would make the VA-PAMAID easier to use and more effective for elderly visually impaired individuals

Technische Biologie des Tasthaar-Sinnessystems als Gestaltungsgrundlage für taktile stiftführende Mechanosensoren

In der vorliegenden Arbeit wird ein Konzept des Reizleitungsapparates vorgestellt, welches die Aufbereitung und Systematisierung biologischen Wissens ermöglicht und sich für eine Anwendung auf technische Sensoren zur Identifikation des Optimierungspotentials und Entwicklung von Lösungsansätzen eignet. Am Beispiel taktiler stiftführender Sensoren wird dieses Konzept als methodische Leitlinie angewendet. Als Untersuchungsobjekt wird aufgrund seiner technisch relevanten Charakteristika das Tasthaar-Sinnessystem von Säugetieren mit den peripheren Strukturen Haarschaft, Follikel-Sinus-Komplex und Mechanorezeptoren ausgewählt. Ziel der Untersuchungen dieses Sinnesorgans ist nicht die detaillierte Aufklärung aller funktionellen Zusammenhänge von der Peripherie bis zu der neuronalen Verarbeitungskette, sondern eine Abstraktion entscheidender Grundprinzipien, die den Ausgangspunkt für Lösungsansätze sensortechnischer Problemstellungen darstellen.Nature offers an inexhaustible array of phenomena with potential for technical application. A wide range of designs inspired by ideas from biology often fails because no transfer method from research to industrial implementation exists. This work introduces a concept for systematic analysis of function determining principles of biological sensor organs. The concept is based on comparative examination of biological sensor organs and technical sensor systems. Target-oriented evaluation and systematization of biological knowledge in the technological context is accomplished by using the so called stimulus-leading-apparatus concept. Furthermore, this concept can be applied to technical sensor systems to identify design strategies and optimization potential. The concept is tested on tactile sensors. Biological subject of study is the whisker system of mammals because of its technical relevance. Hair shaft, follicle-sinus-complex (FSC) and mechano receptors are the interesting peripheral structures of the whisker system. Aim of the study is not a detailed analysis of all functional correlations from periphery to neural processing but an abstraction of the essential principles which can initiate solutions for technical sensor problems. Therefore, the biological system is analyzed by means of technical methods and models. The whisker system periphery is examined as a beam with a compliant clamping featuring variable stiffness. Structural and mechanical parameters of the hair shaft are determined experimentally. Deductive methods of modeling are used to analyze the follicle-sinus-complex. A mechanical model reduced to basic principles is introduced. The reaction to external forces is studied and compared using static and even dynamic models. Finally, some ideas for optimizing technical tactile sensors are developed. Emphasis is on design concepts for the stimulus receiving structure and the realization of a compliant clamping with variable stiffness.Die Natur bietet ein unerschöpfliches Potential an Phänomenen mit technischer Relevanz. Oft scheitert die breite Anwendung von Ideen aus der Biologie am Fehlen einer effektiven Transfermethode zwischen Forschung und industrieller Anwendung. In der vorliegenden Arbeit wird basierend auf einer vergleichenden Betrachtung biologischer Sinnesorgane und technischer Sensorsysteme ein Konzept zur systematischen Analyse der funktionell entscheidenden Grundprinzipien biologischer Sinnesorgane dargestellt. Dieses Konzept des Reizleitungsapparates ermöglicht die Aufbereitung und Systematisierung biologischen Wissens und eignet sich für eine Anwendung auf technische Sensoren zur Identifikation des Optimierungspotentials und Entwicklung von Lösungsansätzen. Am Beispiel taktiler stiftführender Sensoren wird das Konzept zum Reizleitungsapparat als methodische Leitlinie angewandt. Als Untersuchungsobjekt wird aufgrund seiner technisch relevanten Charakteristika das Tasthaar-Sinnessystem von Säugetieren mit den peripheren Strukturen Haarschaft, Follikel-Sinus-Komplex und Mechanorezeptoren ausgewählt. Ziel der Untersuchungen dieses Sinnesorgans ist nicht die detaillierte Aufklärung aller funktionellen Zusammenhänge von der Peripherie bis zu der neuronalen Verarbeitungskette, sondern eine Abstraktion entscheidender Grundprinzipien, die den Ausgangspunkt für Lösungsansätze sensortechnischer Problemstellungen darstellen. Daher erfolgt die Aufarbeitung der biologischen Kenntnisse unter Zuhilfenahme ingenieur-wissenschaftlicher Methoden und Modelle. Die Peripherie des Tasthaar-Sinnesorgans wird als Biegebalken mit nachgiebiger Lagerung interpretiert, deren Steifigkeit aktiv einstellbar ist. Während der Haarschaft bezüglich seiner Struktur und der mechanischen Eigenschaften mit verschiedenen experimentellen Methoden untersucht werden kann, muss bei der Analyse des Follikel-Sinus-Komplexes auf deduktive Methoden der Modellbildung zurückgegriffen werden. Es wird ein auf Grundprinzipien reduziertes mechanisches Modell vorgestellt und dessen Reaktion einerseits als statisches und andererseits als dynamisches System auf verschiedene Erregerkräfte analysiert. Abschließend werden Ansatzpunkte zur Optimierung taktiler stiftführender Sensoren entwickelt. Schwerpunkte liegen neben Gestaltungsvorschlägen für die reizaufnehmende Struktur auf der Umsetzung einer nachgiebigen und in ihrer Steifigkeit einstellbaren Lagerung

A high speed sensor system for tactile interaction research

Schürmann C. A high speed sensor system for tactile interaction research. Bielefeld: Bielefeld University Library; 2013.In this work we will describe and implement the first tactile sensor system that combines the properties of modularity with a very high sensing speed, a high sensitivity and a high spatial resolution. This unique combination of features enables researchers to develop novel applications and makes it possible to replace task specific tactile sensors with a single system. The very high sensing speed of the system allows for slip detection during robot grasping. And as all our sensor cells are sampled with the same high frequency, our system can even enable the slip detection for multiple contact points at the same time. This high speed was made possible through the development of a highly integrated parallel sensor sampling architecture. The modularity of the system allows it to be employed in a multitude of applications. Tactile sensitive surfaces of various dimensions can be easily realized through a very simple ’plug and use’ principle without the need for software configuration by the user. This was made possible by developing a new bus system that allows the relative localization of the participants. Our system can be used to create tactile sensitive table surfaces with a large amount of sensor cells and due to its high speed design still provide for real time frame rates. The flexibility and high performance of the system enabled us to develop a tactile sensitive object that allows the continuous high speed monitoring of human finger forces. For this we solved the problem of integrating the tactile sensors to allow free movement of the object, while maintaining a constant high rate of data capture and realizing a low latency synchronization to external devices. The high sensitivity of the system was made possible through technical innovation in the state of the art of resistive based tactile sensors. We did so by creating an optimized sensor cell shape and investigating the behavior of different sensor materials. The knowledge gained in this process was further used to advance the existing method of sensor normalization into a real time method. We will present a range of tactile interaction scenarios that have been realized with the tactile sensor system named Myrmex. These scenarios include the investigating of human grasp force control during a pick and place task, a tactile table for integration into an intelligent household and a tactile table for the manipulation of virtual clay as a form of finger training. In addition we will present a selection of scenarios where the Myrmex system was employed by other researchers, as in using the sensor modules as (large) tactile fingertips on robot arms to implement tactile servoing or slip detection during object grasping. The system has also been used to study human finger forces as well as investigating novel methods for prosthesis control. The positive results from all the scenarios support our conclusion that the developed Myrmex system is a very valuable and reliable tool for the research of tactile interactions